A generator set or “genset” is a device that converts fuels such as gasoline or diesel fuel into electrical energy. One of the main components of a generator set is an internal combustion engine. Internal combustion engines typically produce the more shaft power as engine speed increases. Noise and fuel consumption typically increase as speed increases. An engine of a variable speed genset can operate at a speed that varies in accordance with the power demand of the load. When the load is light, the engine operates at a lower speed. When the load is heavier, the speed of the engine can increase in response to the load increase. Thus, fuel consumption can be reduced and emissions and noise associated with the operation of the engine can be minimized. Since the engine may not be able to respond as quickly as the load can increase, the speed of the engine at a light load can include a speed margin to ensure that excess power is available to respond to load increases. The excess power may result in wasted fuel and unwanted emissions and noise.